Greece:
1. Postal Offices: You can purchase Greek postage stamps at the main post offices ("ELTA") located in cities and towns throughout Greece.
2. Philatelic Offices: Specialized philatelic offices, often located within the main post offices, sell postage stamps and other philatelic items.
3. Stamp-Selling Kiosks: In some tourist areas, you might find automated stamp-selling kiosks where you can purchase stamps using cash or credit cards.
4. Online: Check the official ELTA website (elta.gr) to see if they offer an option to purchase postage online and have the stamps delivered to your desired location.
Turkey:
1. PTT Office: Turkish postal services are provided by PTT (Post and Telegraph Organization). Look for PTT offices in cities and towns across Turkey to purchase Turkish postage stamps.
2. Philatelic Offices: PTT operates specialized philatelic offices where you can find a wider variety of stamps and postal collectibles.
3. Authorized Retailers: Some tobacco and newsstand shops may also sell Turkish postage stamps.
4. Online: Visit the PTT website (ptt.gov.tr) to explore their online services and check if they offer the option to purchase postage stamps online.
Sending Postcards to the United States:
1. Stamps: Make sure you purchase enough stamps to cover the postal rate for sending postcards from Greece or Turkey to the United States. The postal rates may change, so it's important to verify the current tariffs at the time of mailing.
2. Addressing: Clearly address the postcards with the recipient's name and address in the United States. Use legible handwriting or type the details.
3. Customs Declaration: If you're sending any items enclosed in the postcards (e.g., small souvenirs), you may need to fill out a customs declaration form. Check with the postal staff or the customs regulations of the respective countries for any additional requirements.
4. Drop-off: Once your postcards are stamped and addressed correctly, drop them into the designated mailboxes at the post offices or authorized postal agencies.
I recommend checking the postage rates and regulations for both Greece and Turkey's postal services closer to your travel date to ensure the information is accurate and up to date.